Mechanical stoker



Patented Oct. 6, 1936 UNITED .STATES PATENT OFFICE Application October 7, 1931,' Serial No. 567,399

s6 Claims.

This invention relates generally to fuel feeding devices, and more particularly to an improved vform of mechanical Stoker.

` An object of the presen-t invention is to l.provide a mechanical Stoker of .simple and economical construction, and suitable for .use with `domestic furnaces and other forms of heating apparatus.

Another object of this invention is to provide a mechanical stoker `of compact form, which is 150 mounted upon, and movable with, afurnacedoor or like member, such that installation can be made on previously erected "furnaces by simply attaching the door carrying the Stoker, and such that access to the interior of .the furnace can be 215 had for any purpose, by moving the `door to its `open position.

Another object of this invention is to provide a mechanical stoker having novel power means .for actuating .the same.

`A further object of this invention is to `provide a mechanical stoker havinga. fuel-feeding plunger which is operated by means including a hy- 4 draulically .actuated diaphragm.

Still another object of this invention is .toprovide mechanical stoking apparatus having novel control means, Vand embodying .a .fuel feed tube which is rotatable about its axis to facilitate .the charging of the fuel hopper.

Other objects and advantages of this invention 430 will be apparent from the following description,

. when taken in conjunction with `the accompany- .ing sheets of drawings, wherein Figure 1 isa side elevational view of a mechanical stoker embodying .my invention;

Fig. 2 is a front elevation thereof;

Fig. 3 is a plan view thereof with the hopper removed and showing a portion `of the furnace in section; v A

Fig. 4 is a vertical sectional elevation taken .on

Fig. 5 is a partial sectional plan view taken on line 5-5 of Fig. 2;

e Fig. 6 is a sectional .elevation taken on line -6-6 of Fig. 4; y

Fig. 7 is a plan view showing a portion of the mount with the feed tube removed;

Fig. 8 is a sectional view taken on line 88 of Fig. 5;

Fig. 9 is a sectional view'of onefof the control valves; and

Fig. l0 is a sectional View of a thermostat forming a part of the automatic control means vfor the Stoker.

.In the drawings, to which detailed reference Vwill presently be made, I have shown the preferred embodiment of .my invention rin .the form of a mechanical .stoken which .is of simple and compact construction, economical lin operation, andespeciallysuitable .for use with .domestic furnaces. YBefore .proceeding with a detailed descrip- --5 tion of .the device, it should be understood that my .invention may be .embodied in structural :formsother .than that .herein illustrated, and .that the utility of the deviceisby no means restricted to'domestic .heating apparatus. e 'I0 In its preferred embodiment, as illustrated in thedrawings, mymechanical stoker is of the overfeed type, .and in general comprises .a feed Vtube II) "having .a .reciprocable l.plunger .II therein, and .a

Yhopper J2 arranged to supply fuel .to the .feed tube. i5 The feed .tube .may 4be of vany appropriate shape, but, as shown in this instance, is of circular crosssection .and is .made of a suitable length to ex- Atend through an opening .provided -in 'the hinged door 1.3 of the .furnace .14, so as to `position the 2'0 open inner end of the tube .aboverthe fire-pot .I5 Yof .the furnace. 1 Y

According to vmy invention, the .feed -tube I0 with the hopper I2 .attached thereto is supported in .a ybracket I6 which may be secured to, but .is 5 preferably formed integral with, the door I3. As shown in Figs. 4 and 6 of the drawings, this Ybrat'zk- Vet isof hollow .or inverted saddle lform having a substantially semi-,cylindrical .recess therein, and is arranged .to extend .laterally adjacent the open- '530 ing provided .in the door for lthe feed tube.. The recess `of .the .bracket corresponds generally with the external contourof the feed tube, so that when the latter is inserted through the opening .orf .the ydoor I3, it will be supported in the recess #'35 of the `bracket by the engagement of itsfouter surface y.with .the bearing portions 1I *I of the rbracket .and with the annular edge Il' of the opening inthe door. Thebracket thus forms a .saddlelike support or vmount in which the feed tube .I0 40 is both rotatable about its axis and slidablelongitudinally of its axis, forpurposes presently to be explained.

The sliding movement provided for the feed tube by the bracket I6 permits the tube to be vre- 45 Vtracted'relative to the opening of the door I3 whenever it may be desirable to .swing the latter ,toits open position., such as when the fuel bed needs to be `stirredor lighted, or when trash is to be burned .in the furnace. 'Ilhe vretraction vvof y5l) the feed `tube in this manner allows the door to be swung to its open position without linterference between the inner end of the feed tubeand the wall :of 'the furnace door .tting or mount I8. To reduce to .a minimumA the amount' of sliding S55 movement of the feed tube which may be required, I prefer to locate the bracket I6 so that the axis of the feed tube will be as close as practical to the hinge connection I9a upon which the door swings. It will be understood, of course, that the length of the feed tube and the amount of sliding movement necessary will vary in accordance with different types of furnaces, andin those instances where Vthe length of the feed tube is such that no interference occurs between its inner end and the door fitting, no retracting movement whatever is necessary. In the case of a hot air furnace, such as that illustrated in the drawings, retracting movement ofv the feedgtube is usually necessary because the door fitting I8 kbutrwhen the stoker is intended for use with domestic heating plants, this hopper should be sufficiently' large to hold several hours supply of fuel; lThe rotational movement provided for the feed tube inf' the supporting bracket I6 facilitates the `charging of this hopper with fuel, by permitting thehopper'to be swung about the axis of the feed tube'as a center, from the upright feeding position shown inv full lines in Figs. l and 2 to the inclined dotted position shown in Fig. 2. When thehopper has been swung to its inclined position, it can be readily filled with the desired amount of fuel without interference from overheadstructures, such as the flooring which may extend above the Vbasement in which the furnace is located. After the hopper has been charged with fuel, it is swung to its upright position,

from whichthe fuel descends by gravity into the feed tube MIU. As shown in the drawings, the wallsof the-hopper areinclined and so arranged that the fuel will flow freely into the feed tube without sticking or clogging. A t the top of the hopper, the walls are preferably inclined inwardly to form the lip I8 which prevents fuel from falling out while the hopper is in the inclined charging position.

Tolimit the rotational movement ofthe feed tube I0 about its axis, and thereby limit the extent of ,swinging movement of the hopper, I provide a longitudinally extendingtongue ,or rib I9 Yon the outer surface of the feed tube which cooperates with the shoulders or abutments 20 providedfon the bracket rlli lat pointsl adjacent the bearing portions I-1 thereof. Violent jarring vof lthe Stoker, incident to engagement of the tongue I9 with one' of the shoulders 20,#may beprevented by providing resilient bumpers in the form of rubber blocks 2 I, which may-be secured to said shoulders by suitable means, such as the dovetail connection illustrated in Fig. '7. It will be seen from the arrangement described* that the hopper may be swung to either side of the vertical plane passing through the axis of the feed tube, and when the tongue I9 engages one ofV the bumpers 2|, the hopper Will be retained in a convenient position for charging with-fuel. v

For locking and retaining the hopper in its upright or fuell feeding position, I provide locking means in the form of a pair of latches 22, which are pivotally mounted upon the bracket I6. These latches extend laterally outwardly in opposite directions from the center line of the bracket, so as to be readily accessible when the feed tube is to be released andthe hopper swung to its charging position. The inner end portion 23 of each latch is preferably curved upwardly so as to extend through the opening 24, formed in the bottom wall of the bracket I6, for engagement with the tongue I9. The pivotal mountings for the latches are preferably so located that the distribution of the weight of these members will cause the inner ends 23 to normally project/upwardly through the opening 24 and into the path of movement of the tongue I9. When the hopper is to be moved to the charging position, the appropriate latch is swung about its pivotto'retract the end 23 from the opening 24, and allow swingingjnovement of the tongue I9.

, When'the hopper has been charged and is moved is made of considerable length so as to.extend i toits upright position, the tongue depresses and rides over one of the latches and is received and heldin the space'between the ends 23, thus locking the feed tube against further rotation and Yholding the hopper in the fuel feeding position.

To prevent rotation of the hopper while the feed tube is in itsretracted position to permit the door I3 to be swung to the open position, I provide 'a slot 28 in the inner surface of the :bracket recess. 'I'his slot is located in axial alignment with the locked position of the tongue I9,

and uponeretracting movement of the feed tube I0, the tongue enters the slot and effectively holds the feed tubev against rotation while in its retracted'position, thereby avoiding any possibility `of the hopper being tilted and the charge of fuel ber servingV as a means for clamping the edge portion of the diaphragm in fluid-tight engagement-with the end iiange 3i) of the feed tube.-

The diaphragm 21 is operatively connected with the plunger Il by means of the plunger rod 3I. One endv of this rod'is secured to the plunger centrally thereofiwhile the other end of the rod is lsecured-tothe diaphragm vcentrally thereof by means of abearin'g plate 32 and a washer 33 which are clamped against opposite sides of the diaphragm., It will-be seen that the diaphragm n21 forms a movable rear wall for the chamber 28, thus constituting the movable power element of an expansible-chamber motorV which is adapted to move the plunger II toward the door I3, or in 'otherwords, 'in a fuel feeding direction. The

plunger is shown'inF'ig'. l in its Yretracted position, to which it-is moved by a coil spring 34.

3`I1with one of'its ends-fin engagement with an abutment member 35 extending transversely of fthe feed tube, and with its other end in engagement with a spring centering washer 36, which is 'secured tothe plungerfrod vadjacent; the diaphragm 21. Y

VVAny available motive fluid of appropriate na- This spring is-'arrange'd to surround the plunger rod ture may be supplied to the chamber 28* for actuvating the diaphragm 21,'bu`t I prefer to use water discharge ports 39 and 40 formed in the cover' `4| of the chamber.

The valves 31 and 38 are appropriately-'shaped for eflicient cooperation with the valve seats surrounding the ports, and

.are carried by an arm 42 whichV is pivoted upon "thei covere'xtension member-or bracket 43. A

1I to rotate the valve stem in a direction to reduce thesize of the discharge valve opening. This reduction in the size of the v alve opening restricts the discharge opening for the chamber 28, thereby decreasing the rate at which the plunger can be-retracted by the spring 34, and consequently slowing vup the operation of the stoker. The movement of the draft door 12 toward its closed position reduces the supply of air to the furnace and correspondingly checks the rate of combustion. When the room temperature falls, the uid within the chamber 6I contracts and relieves the pressure upon the inner chamber 63. Thereupon the weight 69 is lowered by the transfer of oil from the chamber 64 into the chamber 63. The lowering of the weight SS causes the chain 10Vto be moved upwardly, thus opening the draft door 12, and also rotating the needle of the discharge valve 52 to increase the'size of the discharge opening and thus increase the speed of operation of the stoker. Adjustment for the automatic control of the stokermay be made either by shifting the weight 69 along the lever 61, which may be provided with suitable graduations, or by loosening the nut 13 provided on the stem of the valve 52 and altering the angular relation of the valve stem with respect to the lever 1I. 'Io facilitate this latter adjustment, I provide the disk or dial 14, which may have suitable graduations thereon, and which is secured to the stem of the valve 52. The end of the lever 1I, o-pposite that to which the chain 1D is attached, is provided with an opening for the valve stem, and is adapted to be clamped against the disk 14 by the wing nut 13. After unscrewing this wing nut, the -valve stem may be rotated by means of the disk without altering the position of the lever 1I. When the proper setting of the valve has been attained the wing nut is tightened thereby clamping the lever and disk together.

To assist the bracket I6 in supporting the Stoker mechanism, and the weight of the fuel charge contained in the hopper I2, I provide a depending leg 15 which is secured to the bracket I6 at a point remote from the hinge connection ISa. This leg cooperates with the hinge connection of the door in supporting the weight of the stoker mechanism and the fuel charge, and to facilitate swinging movement of the door, may be provided with suitable roller means, preferably in the form of the caster 16. To provide for a slight variation in the length of the leg 15, such as might be desirable should the caster 16 pass over an uneven portion of the floor, I provide a yielding connection between the lower end of the leg and the caster. This connection may consist of a pintle 'Il on the caster, which slidably telescopes into the lower end of the leg 15, and engages a compression spring 18 housed within the leg. The spring l18 provides a shock absorbing connection between the caster and the leg, and also permits slight vertical movement of the caster when the latter passes over obstacles or uneven places on the oor.

To reduce the amount of friction between the plunger II and the feed tube I0, it may be desirable to provide the latter with an annular bearing surface 80, which is located immediately adjacent the discharge opening of the hopper i 2, and which extends but a short distance axially of the tube. This bearing surface is narrow as compared with the axial length of the plunger and tends to reduce the amount of friction therebetween. 1

Since the feed tube I0 and the casing of the fluid chamber 28 secured to the outer end thereof are both movable with the door` I3, as the latter swings to open and closed position, it is necessary to provide flexible motive uid connections, and for this purposeI prefer to employ flexible rubber hose, or the like, for the fluid supply and discharge conduits 8| and 82.

It will now be readily seen that I have provided a simple and compact form of mechanical stoker which is very economical in operation. It will also be seen that the mounting means which I have provided for the stoker mechanism permits the same to be quickly and easily applied to previously erected furnaces by simply substituting for the original furnace door, the door I3 having the stoker mechanism mounted thereon. In the apparatus which I have provided, the provision for rotation of the feed tube permits the hopper to be swung to a convenient fuel charging position, and the sliding movement provided for the feed tube permits the same to be retracted whenever the operator desires to open the door I3 which may be for purposes of working or starting the fire in the fire-pot of the furnace I4. It will also be seen that I have provided a simple form of actuating means for the stoker adapted to use a readily available supply of motive fluid. Operation and care of the stoker is simplified by the provision of the automatic control means for regulating the speed of operation of the Stoker and the draft door in response to the temperature conditions existing in the room or space to be heated. It will likewise be seen that since a fluid is employed for operating the stoker plunger rather than anY electric motor having a rigid mechanical connection, the chance of damage to the apparatus in the event of clogging of the feed tube, is entirelyY eliminated. With the mechanical stoking means which I have provided a cheap grade of fuel can be used to advantage for domestic heating purposes, since the feeding of the fuel to the fire takes place in very small amounts, which are not'suiic'ient to smother the fire as would be the case if several hours supply of fuel were shoveled into the firepot.

While I have illustrated and described the device of my invention in a detailed manner, it should be understood, however, that I do not intend to limit myself to the precise details 'of construction and arrangements of parts illustrated vand described, but regard my invention as including such changes and modifications as do not involve a departure from the spirit of fthe invention and the scope of the appended claims.

Having thus described my invention, I claim:

1. In a stoker mechanism, the combination of a fuel-feeding conduit, means for advancing the fuel within said conduit, and hydraulically actuated means for driving the fuel advancing means, said hydraulically actuated means comprising a chamber having a flexible wall drivingly associated with the fuel advancing means, fluid supply and exhaust conduits communicating with said chamber, valve means for automatically controlling said conduits to thereby control the movement Vof said fuel advancing means, and other control means for regulating the flow ofA uid through the exhaust conduit to. thereby regulate the speed of operation of the fuel advancing means.

2.v In a stoker mechanism, the combination of a fuel-feeding conduit, means for advancing the fuel along said conduit, and means for actuating the fuel advancing means comprising a chamber having a iiexible Wall drivingly associated with said fuel advancing means, means for supplying fluid pressure to said chamber, means for retracting the fuel advancing means, and means for regulating the rate of discharge of uid from said chamber to thereby control speed of operation of the fuel advancing means.

3. In a mechanical stoker, the combination of a fuel-feeding tube, a plunger in said tube, and means for actuating said plunger comprising a uid chamber associated with said tube, -a flexible diaphragm forming a wall of said chamber and having operative connection with said plunger, valve means for controlling the passage of motive fluid to and from said chamber, snap action mechanism located in said chamber and adapted to actuate said valve means, and control means exterior of said chamber for regulating the rate of passage of motive fluid through said chamber.

4. In a mechanical Stoker, the combination of a fuel-feeding conduit, means for advancing fuel along said conduit, and means for actuating the fuel advancing means comprising a ruid chamber associated with said conduit, a iiexible diaphragm forming a wall of said chamber and having operative connection with said fuel advancing means, valve mechanism for automatically controlling the passage of fluid into and out of said chamber, control means for the discharge passage leading from said chamber, and temperature responsive means for actuating said control means to thereby regulate the speed of operation of said fuel advancing means.

5. In a mechanical stoker, the combination of a fuel-feeding tube, a plunger in said tube, means for actuating said plunger comprising a iiuid chamber associated with said tube, a flexible diaphragm forming a Wall of said chamber and operatively connected with said plunger valve mechanism adapted to. be actuated by said diaphragm for automatically controlling the passage of uid into and out of said chamber, control means for the discharge passage leading from said chamber, temperature responsive means for actuating said control means to thereby regulate the speed of operation of said plunger, and means associated with said control means and providing a passage for maintaining a minimum rate of fluid ilow through said chamber.

6. In a stoker mechanism, the combination of a fuel-feeding conduit, means for advancing the fuel Within said conduit, and hydraulically actuated means for driving the fuel-advancing means, said hydraulically actuated means comprising a chamber having a flexible Wall drivingly associated with the fuel-advancing means, iiuid supply and exhaust conduits communicating with said chamber, valve means for automatically controlling said conduits to thereby control the movement of said fuel-advancing means, and other control means for regulating the W of uid through one of said conduits to thereby regulate the speed of operation of the fuel-advancing means.

ALBERT C. SCHICKLER. 

